I think you're missing the spirit of the discusssion.
Discussion about who's driving slower to try to save on gas in a (recreational) vehicle with a large displacement engine, perfectly capable to do normal operating speed(s) has no spirit. At all.
The discussion started about gas vs. diesel engines, their pros and cons and now it's about who's "feathering" the right pedal more/better. That has absolutely nothing to do with the type of engine you have in your vehicle. Like driving unreasonably slow, for no other reason than to save on fuel, has nothing to do with safety. Obviously everyone's driving the way they want, but don't think for a minute that you're doing a "good job" because you take off from the light agonizingly slow (saving fuel!) or driving slow (safe!) on the highway. In the left lane too, for full effect. You're nothing more than a rolling road hazard, causing frustration as other motorists trying to get around you.
So, can we get back to the original topic, which is gas vs. diesel?
I had a diesel e-350 for a while. (Don't know the gas mileage, never calculated it, don't care). I too, like diesels for their torque, but I don't like the noise. Fact is, I hate the noise that comes with the diesel engine in the E series. I went great lengths to soundproof my van, but ultimately I have failed to get it to acceptable noise level in the cabin, so I sold the thing and I will never get another E series with diesel engine. On the other hand, I had a Sprinter with a diesel engine which was great. The noise wasn't bad at all. Loved the torque and the snappiness with it. I drive a Transit now, mid-roof, mid-wheelbase, gas engine and I really like it. The driving experience is similar to the Sprinter's, even more car-like. I don't miss the diesel.